Bin cold storage. During the storage period, ethylene levels were always
lower than 10 parts per billion
(ppb). For small fruit sampled from
the bottoms of the bins, fruit firmness
decreased from approximately 12.0 lbf
to 4.0 lbf after 10 weeks cold storage
(fig. 2). The greatest drop in fruit firmness
occurred within the first 4 weeks
of storage.
Using the regression equation (Pvalue
c 0.0001, r2 = 0.75) for the relationship
between changes in firmness
versus weeks in air storage for the
bins, we predicted that after 7 weeks
our kiwifruit reached the critical firmness
level for packaging (5.0 lbf). The
kiwifruit lost approximately 0.6 lbf per
week during bin storage in air at 32°F.
The difference in time to reach 5.0 lbf
can be explained by the different storage
conditions in the commercial situation.
Thus, this regression equation
can be used as a tool to predict the potential
storage time under optimum
conditions (ethylene-free air at 32°F).
Firmness measurements should be
done during the storage period to determine
the end of the bin storage period
and a safe packaging date.
Exposed kiwifruit in the tops of the
bins (the worst-case scenario for fruit
damage) lost weight at a constant rate
during the cold-storage period (fig. 2).
The use of canvas covers over the tops
of the bins reduced the rate of water
loss by nearly half. In previous work,
we have observed kiwifruit shriveling
only after fruit water-loss values exceeded
4.0% of the initial fruit fresh
weight. Bruising incidence after packaging
varied from 1.0% to 4.1%. More
bruising occurred on the last two
Bin cold storage.